JASON Hairston, the former NFL star and member of the Trump administration, has died at 47, days after returning from a hunting trip with Donald Trump Jr.

Hairston played for the San Francisco 49ers and the Denver Broncos founded a hunting apparel company called Kuiu after he retired, now a $US50 million company, and become good friends with Trump Jr.

Trump Jr also got him a position with the federal government at the Department of the Interior, where he served as a liaison between the agency’s former head Ryan Zinke and sportsmen’s groups on issues such as conservation and public lands.

Hairston, who is survived by his wife Kirstyn and their two young children, had been hunting sheep with Trump Jr in Canada days before his death, which is believed to have been from CTE (chronic traumatic encephalopathy), suffered during his football days.

While a person may suffer symptoms from CTE, the only way to diagnose it is in a post-mortem examination.

He said in a 2016 interview that he believed he had CTE.

“I played linebacker, and the way I played the game, I led with my head. I played the way they tell us not to play now. I have all the symptoms of CTE,” he said.

Trump Jr paid tribute to his friend on Instagram.

“Jason, I have no words. I will always remember our adventures and sharing a campfire with you,” wrote Trump Jr. on Instagram. “They will be some of my fondest experiences in the outdoors. You were and will continue to be an inspiration to all outdoorsmen and women for generations to come. Thanks for the friendship and the memories buddy. I’m going to miss you.”